This is because Taniguchi shot an 18-over par for the round with an 18-hole score of 88. As For the Win points out, Taniguchi's scorecard looks more like a tropical storm than, well, the scorecard of a professional golfer.
As bad as the round was, Taniguchi didn't even come close to the all-time U.S. Open record for highest score in a single round. That record belongs to J.D. Tucker who notched a mind-bending 157 in 1898.